Sound Attenuating Laminate Materials

ABSTRACT

Sound absorbing or attenuating laminate flooring materials are provided, which are directed to be used in the production of floor covering, floor panels, furniture panels, cabinets, counter-tops and wall panels. As well, the methods for producing such products are provided. In particular, abrasion resistant panels, with a laminated structure, created by forming an assembly which consists of laminating a heat-activated resin impregnated paper wear layer, a decorative layer with printed graphics or a wood veneer decorative layer, a medium density (MDF) or high-density (HDF) natural fiber-based core and a resin impregnated paper balancing layer. To achieve sound absorbing and/or attenuating properties, any or all paper layers may be pre coated with an additional flexible elastomeric coating, film or material prior to assembly of the panel, or the natural fiber core panel may be coated with a flexible elastomeric coating, film or material prior to assembly with the papers. The flexible elastomeric coating, film or material acts to absorb, reduce, and/or ameliorate the sound transmissions inherent in laminated panels.

FIELD OF THE INVENTION

This invention relates to sound absorbing (or sound attenuating)laminate materials, including floor coverings, floor panels, furniturepanels, wall panels, cabinets, counter-tops, and the like, andadditionally includes a method for producing such products. Inparticular, however, the present invention preferably relates to a floorcovering material formed of laminated panels, which might also be calleda laminated floor.

BACKGROUND OF THE INVENTION

It is known that laminated floor can be very noisy. The cause for thisis the way in which the floor panels are produced. In the development ofthis product a great deal of attention was focused by manufacturers tomaking a product that had a hard wear-resistant surface with a moistureresistant core made typically made with a formaldehyde binder and woodparticles. The ultra-hard wear layers applied to the upper and lowerpanel surfaces are harder and higher in density than the wood core layerand thereby tend to generate high pitched sounds. This tends to make thefloor noisy.

The industry has responded to this noise concern by providing varioussound-deadening foam and felt materials that are meant to absorb thesound generated by the laminate floor. However, these soft pads tend toreflect the sounds back into the panel which, being a good soundconductor, transmits the sound back into the room.

This noise problem is so serious that many municipalities do not allowlaminate flooring to be installed in stacked dwellings such as apartmentbuildings and in some cases, do not allow laminate flooring to beinstalled in commercial offices. It should be noted that, typically,wood floors such as solid wood, or engineered wood floors, do notexperience this problem to the same degree, since the wood substrate hasa significantly lower density than the laminate floor core materials,and the urethane wear coatings used on these wood floors are flexibleacting to further absorb sound.

As the name implies, laminate floor panels are made up of severallayers. Typically, a laminate floor comprises a wear layer consisting ofa translucent paper and a thermosetting resin with abrasive particles, adecorative paper or foil, an MDF (medium density fibreboard) or HDF(high density fibreboard) base or core panel, and a paper backing (orbalancing) layer, which is also pre-impregnated with thermosettingresin. The entire loose assembly is placed into a press and compressed,under the supply of heat, in order to become one hardened whole. Thistechnique is known as DPL (Direct Pressure Laminate).

Of course, other production techniques are also possible. For example,first a top layer may be formed which, amongst others, comprises theaforementioned decorative layer and the layer of synthetic materialpresent thereupon, after which this formed top layer is attached to abasic layer or basic structure. This technique is known as HPL (HighPressure Laminate).

Additionally, impressions can be realized in the transparent wear layerin order to imitate a wood grain, stone or other textures, which aretypically present at the surface of real wood or other materials such asceramic tiles, leather, etc. In the prior art, this is typicallyperformed by simply providing a series of impressions in the floorpanels, which impressions typically extend in the same direction or inrandom directions.

SUMMARY OF THE INVENTION

The invention is directed to the production of laminated panels,including floor coverings, and in particular, at floor panels, wherebyone or more layers comprising the laminated structure may be treatedwith an elastomeric coating, film or material, in order to reduce noise.As a result, the aforementioned noise disadvantages of the prior art arereduced, minimized, or eliminated.

A technical solution is thereby offered for absorbing the soundresonances, and thereby reducing the sound level and providing forreduced sound frequency.

Accordingly, in a first aspect, the present invention provides a soundattenuating laminated panel, having a laminate structure comprising aplurality of layers, wherein one or more layers comprising said laminatestructure, have been treated with an elastomeric coating, film ormaterial, so as to form a treated layer, in order to reduce the noisegenerated by said panel.

As usual with the known laminated floor panels, the upper and lowerlaminated layers, typically include printed decorative layers whichpreferably consist of paper which can be pre-treated with an additionalelastomeric coating that may include hollow or solid plasticmicrospheres. However, other materials, either based on paper orcellulose or not, are not excluded.

Alternatively, however, a printed decoration can be printed directly onto the MDF or HDF core layer, and the decorative layer may thereby beeliminated. In such a case, the elastomeric material may be impregnatedonto the decorated core layer, or, in some cases, substituted for thewear layer. In this later case, the elastomeric material can also bemodified to include wear particles for improved wear resistance, asdiscussed herein.

Accordingly, using the concepts of the present invention, the entirepanel assembly may be “tuned” to reduce noise depending upon the desiredor selected characteristics of the core panel. Further, each of thepaper or other layers may receive pre-impregnation and subsequentcoatings of elastomeric material in varying thicknesses. The elastomericmaterial may also be of differing hardness, depending on the desiredlevel of sound reduction.

The aforementioned layer or layers of elastomeric material, which,according to the present invention, is preferably situated throughoutthe core of the paper and above and/or below any or all paper layers,can be composed in any manner. By “elastomeric material” it is meantthat this layer comprises an elastomeric material, applied in anappropriate thickness to reduce sound transmission without impeding thebonding of the paper layers to the core. This layer (or layers) ofelastomeric material may comprise other materials than syntheticmaterials, as well as be composed of several sub-layers. The elastomericmaterial may also be a separate film or films in varying hardnesses andthicknesses. The elastomeric material layer is also typically andpreferably transparent.

The elastomeric noise absorbing pre-impregnation solutions, coatings,films or materials may also be applied directly to the upper and/orlower surfaces of the preferably MDF or HDF core layer. An additionaladvantage to using an elastomeric coating or film, would be toeffectively seal the panel and thereby eliminating or reduce the“off-gassing” of toxins which might be given off by the core panel wheresaid core panel has been produced using formaldehyde, for example, as abinder.

Preferably, this elastomeric coating, film or material consists of orcomprises a natural or synthetic resin with elastomeric properties,which has been applied, for example, in very thin layers to the paperlayers and/or the wood core. The elastomeric coating, film or materialcan be thermoplastic or thermoset.

Substances such as hollow or solid plastic spheres may also be presentin the elastomeric coating or film. The plastic spheres selected may beof various hardness and size depending upon the desired level of soundattenuation. The plastic microspheres may be of the expanding varietywhereby they are gas filled and expand when subjected to heat from thefast-cycle press. The plastic microspheres may also be incorporated intoa film that could be placed between one or more layers of the laminatefloor panel assembly.

A further embodiment of the invention would be, to apply to thecompressed wood core, an elastomeric tack coat with a roll-coatingmachine or curtain coating machine. Further, with this coating stilluncured, a liberal sprinkling of thermoplastic microspheres tocompletely cover the surface could be applied. The panel would thenproceed through a drying oven bonding the thermoplastic microspheres tothe elastomeric tack coat. Any loose excess microspheres not bonded tothe surface would be removed. An optional second coating, such as anelastomeric urethane top coat, would preferably be applied to the coreand the core would proceed through a second drying oven. An assemblyincluding the translucent thermoset wear layer, the decorative paper orfoil, the elastomeric microsphere coated wood core panel and thethermoset paper backing layer would then be placed in a heatedfast-cycle press to fuse the wear layer, the decorative foil, theprepared wood panel, and the backing layer into a laminate floor panel.Subsequent operations may include sizing, edge machining, inspection,and packaging.

As such, in a further aspect, the present invention provides a processfor the production of a sound attenuating laminated panel, such as alaminated floor panel, having a laminate structure comprising aplurality of layers, wherein at least one of the layers of the laminatedpanel have been treated or replaced with an elastomeric coating, film ormaterial, so as to form a treated layer, in order to reduce the noisegenerated by said panel.

Further, although the present invention aims at reducing or eliminatingthe noise created by a traditional laminate floor which includes rigidmelamine-impregnated paper surfaces, it will be understood that soundreduction can also be achieved by applying an elastomeric coating to anexisting laminate panel.

For laminate floor covering, and more particularly for each floor panelconcerned, the same elastomeric coatings may be applied to decorativepapers and foils or even wood veneers. Further, the elastomeric coatingmay be incorporated into the adhesive used for bonding the paper foil orwood veneer to an MDF, HDF or other particleboard panel with the goal ofreducing noise around furniture by making the furniture panels soundabsorbing or sound attenuating. Additionally, it will be noted that anelastomeric film or films may be substituted for the coating.

The invention also relates to laminate floor panels which may beproduced with direct printing technology where the MDF or HDF panels areprinted directly with an ink-jet printer or other printing methods andsubsequently a translucent pre-impregnated thermoset paper wear layer isapplied to the upper surface of the panel, and a pre-impregnatedthermoset paper backing layer is applied to the lower surface of thepanel.

The invention also relates to a method for realizing a floor panel,wherein the wear layer is a thermoplastic/thermoset elastomeric materialinstead of the usual thermoset melamine-impregnated paper wear layer.This wear layer would be inherently sound absorbing and could beassembled, for example, over a decorative paper or vinyl foil or over adirectly printed panel MDF or HDF wood core, and a paper orthermoplastic balance layer.

Preferably, the floor panels are made according to the classictechniques for forming HPL (High Pressure Laminate) or DPL (DirectPressure Laminate). With HPL, the individual layers of the planks ortiles are fixed together in separate stages. This technique uses acombination of both pressure and heat and the result is usually a wearlayer that is thicker and therefore harder wearing than that oflaminates made by Direct Pressure. If the flooring is made using the DPLmethod then the individual layers that make up the tiles or planks willfirst be arranged in their required position and then pressed and bondedtogether at the same time. Typically, the floor panels hereby are formedfrom larger “plates”.

Typically, these plates would be comprised of (i) a pre-impregnated wearlayer comprising a sheet formed from a resin impregnated paper sheetwhich may include aluminum oxide or other abrasion resistant particleswith a (typically) thermosetting resin which sheet may be treated withan elastomeric coating or film; (ii) a decorative layer that may betreated with an elastomeric coating or film; (iii) an MDF or HDF base orcore that may be treated with an elastomeric coating or film; and/or(iv) a lower balancing layer (or backer layer) consisting of apre-impregnated paper layer comprising a sheet formed from a resinimpregnated paper sheet with a thermosetting resin which sheet may betreated with an elastomeric coating or film, or optionally anelastomeric film or coating applied directly to the core layer. Otherlayers might also be included.

The application of an elastomeric coating or film may occur during theproduction of any or all of the components of the laminate assembly orin the manufacture of any or all of the individual components whichcomprise the laminated assembly. The loose assembly is subsequentlytransferred to a heated press and then compressed to form a wholelaminated panel, whereby pre-impregnated (typically) thermosettingresins provide for adhesion and hardening and the thin elastomericcoating or film(s) act as the sound absorbing or attenuating layer(s).

Simultaneously to pressing, the laminated panel impressions arepreferably applied, as the press, at the surface of the pressing partcomes into contact with the upper side of the aforementioned plate. Thepressing plate comprises the relief features which are typically desiredin the production of a laminated floor panel. The resultant laminatedfloor panel thereby includes a thin sound-absorbing or attenuatingcoating on one or more layers, in order to reduce or eliminate soundtransmission in accordance with the invention.

In a further embodiment, a thin elastomeric coating or film may also beapplied to the edge surfaces that incorporate the panel joint. The typeof joint may be a traditional tongue and groove joint, a click joint, ahinge type joint and any combination of these or any other type of jointsystem used to join two or more panels. Application of the elastomericcoating will act to further reduce noises created when the laminatefloor panels are installed in a floating manner over a flexible foam orfelt backing material that may also act as a vapor barrier. This furtherembodiment will also preferably act to reduce or eliminate any squeakingcaused by flexing of the joint when walking over the floor.

The above-mentioned further embodiment will also act to seal the edgesof the floor panel from moisture and again act to reduce or eliminateany potential for off-gassing of toxins such as formaldehyde, forexample.

BRIEF DESCRIPTION OF THE DRAWINGS

With the intention of better showing the characteristics of theinvention, hereafter, as an example without any limitative character,several preferred forms of embodiment are described, in the accompanyingdrawings, wherein:

FIG. 1 represents a cross-sectional view of a typical laminate floorcovering which is composed of layers including melamine impregnatedpapers;

FIG. 2 represents showing a thin elastomeric coating or film applied tothe underside of the transparent wear layer which has beenpre-impregnated with an elastomeric solution polymer that penetratesinto the paper, in accordance with one embodiment of the presentinvention;

FIG. 3 show a thin elastomeric coating applied to the underside of thedecorative paper layer which has been pre-impregnated with anelastomeric solution polymer that penetrates into the paper;

FIG. 4, shows an elastomeric coating or film applied to the uppersurface of the MDF or HDF core;

FIG. 5, shows a thin elastomeric coating or film applied to the upperand lower surfaces of the MDF or HDF panel;

FIG. 6, shows a transparent thermoplastic wear layer applied over aprinted paper that has been pre-impregnated with an elastomeric solutionpolymer that penetrates into the paper or vinyl decorative foil appliedto the upper surface of the MDF or HDF panel;

FIG. 7 shows an elastomeric coating or film applied as a wear layer, tothe upper surface of a printed MDF or HDF core; and

FIG. 8 shows a sound wave generated by a single impact to an elastomericcoated sample, according to the present invention

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

FIG. 1 is an expanded 3-dimensional view of a typical laminate floorpanel which incorporates a thermosetting melamine resin-impregnated wearlayer 1 (which may incorporate abrasive particles), a decorative foil orpaper 2 (which may be coated with a thermosetting resin), an MDF or HDFbase or core panel 3 made from natural fibres and a thermosetting resin,and a thermosetting melamine resin-impregnated paper backer layer 4.

FIG. 2 is an expanded cross sectional view of a laminate floor panel ofthe present invention which incorporates a thermosettingresin-impregnated paper wear layer 5 that has been pre-impregnated withan elastomeric solution polymer that penetrates into the paper which mayincorporate abrasive particles, a thin transparent elastomeric coatingor film for sound absorbing or attenuating properties 6 which has beenpre-applied to wear layer 5, a decorative foil or paper 7 that has beenpre-impregnated with an elastomeric solution polymer that penetratesinto the paper which may be coated with a thermosetting resin, an MDF orHDF core panel 8 made from natural fibres and a thermosetting resin, anda thermosetting resin-impregnated paper backer layer 9 that has beenpre-impregnated with an elastomeric solution polymer that penetratesinto the paper.

FIG. 3 is an expanded cross sectional view of a laminate floor panelwhich incorporates a thermosetting resin-impregnated paper wear layer 10that has been pre-impregnated with an elastomeric solution polymer thatpenetrates into the paper and which may incorporate abrasive particles,a decorative foil or paper 11 that has been pre-impregnated with anelastomeric solution polymer that penetrates into the paper and whichmay be coated with a thermosetting resin, a thin elastomeric coating orfilm 12 for sound absorbing or attenuating properties which has beenpre-applied to foil or paper 11, an MDF or HDF core panel 13 made fromnatural fibres and a thermosetting resin, and a thermosettingresin-impregnated paper backer layer 14 that has been pre-impregnatedwith an elastomeric solution polymer that penetrates into the paper.

FIG. 4 is an expanded cross sectional view of a laminate floor panel ofthe present invention which incorporates a thermosettingresin-impregnated wear layer 15 that has been pre-impregnated with anelastomeric solution polymer that penetrates into the paper and whichmay incorporate abrasive particles; a decorative foil or paper 16 thathas been pre-impregnated with an elastomeric solution polymer thatpenetrates into the paper which may be coated with a thermosettingresin; a thin elastomeric coating or film 17 for sound absorbing orattenuating properties 17 which has been pre-applied to an MDF or HDFcore panel 18; an MDF or HDF core panel 18 made from natural fibres anda thermosetting resin; and a thermosetting resin-impregnated paperbacker layer 19 that has been pre-impregnated with an elastomericsolution polymer that penetrates into the paper.

FIG. 5 is an expanded cross sectional view of a laminate floor panelwhich incorporates a thermosetting resin-impregnated paper wear layer 20that has been pre-impregnated with an elastomeric solution polymer thatpenetrates into the paper and which may incorporate abrasive particles,a decorative foil or paper 21 that has been pre-impregnated with anelastomeric solution polymer that penetrates into the paper and whichmay be coated with a thermosetting resin, a thin elastomeric coating orfilm 22 a for sound absorbing or attenuating properties which has beenpre-applied to the upper of an MDF or HDF core panel 23, a thinelastomeric coating or film 22 b for sound absorbing or attenuatingproperties which has also been pre-applied to the lower surface of anMDF or HDF core panel 22 b, and a thermosetting resin-impregnated paperbacker layer 24 that has been pre-impregnated with an elastomericsolution polymer that penetrates into the paper.

FIG. 6 is an expanded cross sectional view of a laminate floor panel ofthe present invention which incorporates a transparent thermoplasticwear layer 25, a decorative foil or paper 26 that has beenpre-impregnated with an elastomeric solution polymer that penetratesinto the paper which may be coated with a thermosetting resin, a thinsound absorbing or attenuating elastomeric adhesive or film 27 a whichhas been pre-applied to the upper of an MDF or HDF core panel 28, a thinsound absorbing or attenuating elastomeric adhesive or film 27 b whichhas been pre-applied to the lower surface of an MDF or HDF core panel,and a thermosetting resin-impregnated paper or thermoplastic backerlayer 29 that has been pre-impregnated with an elastomeric solutionpolymer that penetrates into the paper.

FIG. 7 is an expanded cross section view of a laminate floor panel ofthe present invention which incorporates an MDF or HDF core layer 32with a backer layer 33. A decorative pattern 31 has been directlyprinted on to core layer 32, and an elastomerically modified wear layer30 consisting of a translucent paper, is applied directly over theprinted decorative pattern 31.

In all examples, the “elastomeric” resin could, in fact, be made fromany thermoset or thermoplastic elastomeric material in various formsincluding liquid, solid, film, one component or multi-component;thermoset, thermoplastic (TPE), solution polymer or water-based orsolvent-based dispersion and latexes. Either block or alternating orrandom copolymers may be used. The said material can be based on, butnot limited to the following polymers, namely: PE, all grades (LLDPE,LDPE, MDPE, HDPE); Polyurethane; Polypropylene; Ethylene vinyl acetate;Ethylene vinyl alcohol; Polyester; Polyolefin (TPO); modifiedMelamine-based thermoset resins; ESI—ethylene styrene interpolymer orany of the styrene acrylic copolymers; rubber based materials, NBR(nitrile Butadiene), SBR (styrene butadiene), CR (chloroprene),silicone, fluorocarbon, acrylamide, epichlorohydrin, carboxylated,natural and synthetic latexes.

The thickness of the elastomeric coating is preferably from 1 micron to3 mm, but thinner or thicker coatings might also be used. Theapplication of the elastomeric material shall not be limited to thecoating of the core or the layering papers top or bottom. Theelastomeric material may comprise of a modified paper or flexible foilor a paper or foil with an elastomeric coating.

As such, the elastomeric thermosetting resin could also be a flexibleresin system used to coat or impregnate any or all of the paper or corelayers, and/or combinations thereof. Preferably, this elastomericmaterial may be in the form of a water-based dispersion or a water-basedor solvent-based solution polymer which by itself may have definedlimits of elongation of 0-2000%, a 100% modulus between 0-1500 psi, anda tensile strength between 0-8000 psi by ASTM D-412

According to a variant, the elastomeric material and the decorativelayer, already before their application on the base (or core) panel, mayconsist of a single layer, for example, in that the decorative layer issoaked such that sufficient elastomeric material is present thereupon toprovide the sound absorbing properties therein. It is also not excludedto start from a layer of elastomeric material which is provided with adecorative layer at the underside, which layer is exclusively formed bya print. The term print must be interpreted in the broadest sense, andthereby any technique is intended to provide for a decorative topsurface for the panel.

Also, a white paper, that has been pre-impregnated with an elastomericsolution polymer that penetrates into the paper and subsequently coatedwith an elastomeric resin may be applied to the HDF or MDF core panelfor the purposes of forming a neutral background if a direct printingtechnique is used to decorate the panel.

A transparent wear layer consisting of a thermoplastic material such asPVC (polyvinyl chloride), TPO (thermoplastic olefin), or Polypropylenein various thicknesses may also be applied over the decorative papers orprinted surface to act as the wear layer depending upon the desiredperformance properties.

The laminated assembly as described herein refers to a core panel suchas HDF or MDF material made from natural fibers using PMDI orformaldehyde, other binders and other additives including waxes, asdescribed herein, and must be interpreted in the broadest sense.Variations in the type of natural fibers to produce the core panel, thedensity of the natural fiber based core panel, the use of differentresins or bonding agents, composites made with combinations of differentfibers, and core panels made from other materials which may be syntheticor metallic such as extruded plastics and flexible core materials, mayfurther all benefit from the invention described herein aimed atreducing noise and absorbing sound when objects come into direct orindirect contact with the panel.

The elastomeric film or coating may be applied in a web pattern in sucha way as to further increase or modify the sound absorption properties.

EXAMPLE Example 1

Dry milled hardwood fibers (650 g) with an average diameter of 0.5 mmand a moisture content of 5% were used to produce the sample. The fiberswere blended with polymeric diisocyanate (PMDI) resin (42 g) (MR Litefrom Bayer), which is reactive at elevated temperature. The isocyanatethen added to the hardwood fibers in a mixer bowl at room temperature(26° C.), and the materials were blended for approximately 8 minutes ina lab mixer fitted with a single oscillating mix blade. The resultantbinder-coated fibers were sprinkled uniformly by hand into a 30×30 cm(L×W) frame and compacted in a platen press and pressed to the intendedthickness of 7.5 mm at a pressure of up to 68 bar for 150 sec at 130° C.The resulting 7.5 mm thick sample panel was rigid and exhibited ahardness of 78 on the Shore D scale. The hot board was placed on a wirecooling grill.

After cooling, a portion of one side of the upper surface of the boardwas treated with a flexible elastomeric coating comprised of analiphatic water-based polyurethane polyester-based dispersion having anelongation of 400% with a 100% modulus of 800 psi, and a tensilestrength of 4000 psi, and allowed to dry.

Decorative papers printed with a woodgrain pattern with a weight ofapproximately 65 g/m2 as normally used in the production of laminateflooring were cut to 20×30 cm size. A laboratory roller impregnator thatconsisted of a metal tray under an assembly with two rollers was used. Apre-impregnation solution bath was prepared consisting of 50% H20 and50% WB-90 PURchem Solution Polymer and poured into the tray. Each sheetwas placed in the solution polymer and gently pulled between the rollersto remove any excess. The sheets were dried to remove excess moisture inan oven with a temperature of 90° C. for 3 minutes.

A second bath with a solution was prepared consisting of 20% H20 and 80%WB-100 PURchem Polyurethane Water-Based Dispersion and poured into thetray. Each sheet was placed in the solution polymer and gently pulledbetween the rollers to remove any excess. The sheets were dried toremove excess moisture in an oven with a temperature of 90° C. for 3minutes.

The decorative papers were coated with a solution consisting of 10% H20and 80% WB-110 PURchem Polyurethane Water-based Dispersion resin withInternal Mold Release (IMR)+10% of Corundum particles (Al2O3) withinternal mold release. Each sheet was placed in the solution and gentlypulled between the rollers to remove any excess. The sheets were driedto remove excess moisture in an oven with a temperature of 90° C. for 3minutes. The dried decorative sheets were set aside.

Once the sheets were pre-impregnated and subsequently dried, the looseassembly consisting of the 7.5 mm thick wood core board as describedabove, the impregnated decorative sheet, and an impregnated kraft paperbacking sheet was placed in 100 ton heated hydraulic press with upperand lower platens having a surface temperature of 150° C. The pressmachine was equipped with a chromium-plated steel press plate having awoodgrain texture installed on one surface that is designed to makeimpressions into the printed decorative paper. The press was closed witha surface pressure of 45 kg/m2 for 20 seconds to cure and bond the looseassembly forming a laminate floor panel sample with a wood-grain designand corresponding surface texture with the wood core board. Combined,the sheets in this example had a film build of 150 g per m2.

It should be noted that this amount is completely variable dependentupon the desired level of sound absorption required.

As the end of the cycle, the sample was removed from the press, allowedto cool and cut to the desired dimensions.

The uncoated and coated samples from the same board, examples CONTROLand FP1 (coated) were tested for sound.

Brief Description of the Sound Test

The results of the sound comparison for Example 1 is shown in theaccompanying drawing. FIG. 8 depicts the sound waves based on a singleimpact to an elastomeric coated sample “FP1”, and uncoated test sample“CONTROL” which were cut from the same base panel.

A sound testing device consisting of a push-button switch, a 9 voltbattery and a small solenoid with a light spring-retraction mechanism,surrounded by foam insulation and housed in a plastic box isolated fromthe sample surface with rubber pads was used to produce the ping sounds.Upon closing the circuit, electrical current creates a magnetic field inthe solenoid moving the spring-retractable core rod through a hole inbottom of the plastic box to strike the surface of the test piece.

The sound recordings were made using the program Audacity, with an AppleMacBook Pro laptop computer. Individual samples CONTROL and FP1 wereplaced directly in front of the built-in computer microphone. Eachsample was placed on a sheet of 2 mm thick foam laminate floor underlaymaterial (typical of what would be used as underlay material in theindustry).

The CONTROL sample exhibits significantly more concentrated sound wavesfor a longer time period. The FP1 sample is significantly quieter. Thesound pattern represented in the FIG. 8 shows a decrease on the decibelrating by approximately 30%, a lower pitch, and significant reduction inthe overall length of the sound pattern.

Samples with additional elastomeric coatings will have even better soundabsorption or attenuating properties enabling someone skilled in the artto tune out unwanted noise reduce reverberation within the panel.

The present invention is in no way limited to the forms of embodimentdescribed as an example and represented in the figures. On the contrary,the present invention, including floor covering, and more particularlysaid panels, as well as the methods described herein, may be realized indifferent variants without leaving the scope of the invention.

Thus, there has been provided, in accordance with the present invention,a sound attenuating laminated flooring material, and a process forproducing such a sound attenuating laminated flooring material whichfully satisfies the goals, objects, and advantages set forthhereinbefore. Therefore, having described specific embodiments of thepresent invention, it will be understood that alternatives,modifications and variations thereof may be suggested to those skilledin the art, and that it is intended that the present specificationembrace all such alternatives, modifications and variations as fallwithin the scope of the appended claims. Unless otherwise specificallynoted, the features described herein may be combined with any of theabove aspects, in any combination.

Additionally, for clarity and unless otherwise stated, the word“comprise” and variations of the word such as “comprising” and“comprises”, when used in the description and claims of the presentspecification, is not intended to exclude other additives, components,integers or steps. Moreover, the words “substantially” or “essentially”,when used with an adjective or adverb is intended to enhance the scopeof the particular characteristic; e.g., substantially planar is intendedto mean planar, nearly planar and/or exhibiting characteristicsassociated with a planar element.

Further, use of the terms “he”, “him”, or “his”, is not intended to bespecifically directed to persons of the masculine gender, and couldeasily be read as “she”, “her”, or “hers”, respectively. Also, whilethis discussion has addressed prior art known to the inventor, it is notan admission that all art discussed is citable against the presentapplication.

1. A sound attenuating laminated panel, having a laminate structure comprising a plurality of layers, wherein one or more layers comprising said laminate structure, has been treated with an elastomeric coating, film or material, so as to form a treated layer, in order to reduce the noise generated by said panel.
 2. A sound attenuating laminated panel as claimed in claim 1, wherein said laminated panel is a floor covering, and in particular, a floor panel.
 3. A sound attenuating laminated panel as claimed in claim 1, wherein said laminated panel comprises a decorative layer, a core layer, a backing layer, and optionally, a wear layer.
 4. A sound attenuating laminated panel as claimed in claim 1, wherein said treated layer has been formed by pre-impregnating a selected layer, with said elastomeric coating, film or material prior to production of said laminated panel.
 5. A sound attenuating laminated panel as claimed in claim 1, wherein said elastomeric coating, film or material is a liquid, solid or film.
 6. A sound attenuating laminated panel as claimed in claim 1 wherein said elastomeric coating, film or material comprises a natural or synthetic resin with elastomeric properties, applied to the paper layers and/or the wood core.
 7. A sound attenuating laminated panel as claimed in claim 5, wherein said elastomeric coating, film or material is a one component or multi-component; thermoset, thermoplastic (TPE), solution polymer or water-based or solvent-based dispersion and latexes.
 8. A sound attenuating laminated panel as claimed in claim 7, wherein said elastomeric coating, film or material is based on polyethylene (PE) of all grades (including LLDPE, LDPE, MDPE, HDPE); Polyurethane; Polypropylene; Ethylene vinyl acetate; Ethylene vinyl alcohol; Polyester; Polyolefin (TPO); modified Melamine-based thermoset resins; ESI—ethylene styrene interpolymer or any of the styrene acrylic copolymers; rubber based materials, NBR (nitrile Butadiene), SBR (styrene butadiene), CR (chloroprene), silicone, fluorocarbon, acrylamide, epichlorohydrin, carboxylated, natural and synthetic latexes.
 9. A sound attenuating laminated panel as claimed in claim 1, wherein said elastomeric coating has a thickness from 1 micron to 3 mm.
 10. A sound attenuating laminated panel as claimed in claim 1, wherein said elastomeric coating is used in the form of a water-based dispersion or a water-based or solvent based solution polymer.
 11. A sound attenuating laminated panel as claimed in claim 10, wherein said water-based dispersion or water-based or solvent based solution polymer provides a coating having defined limits of elongation of 0-2000%, a 100% modulus between 0-1500 psi, and a tensile strength between 0-8000 psi by ASTM D-412.
 12. A sound attenuating laminated panel as claimed in claim 3, wherein said elastomeric material is impregnated onto the decorated core layer, or wherein said elastomeric material is substituted for said wear layer.
 13. A sound attenuating laminated panel as claimed in claim 3, wherein said elastomeric material is applied directly to the upper and/or lower core layer.
 14. A sound attenuating laminated panel as claimed in claim 3, wherein said core layer is an MDF or HDF wood core.
 15. A sound attenuating laminated panel as claimed in claim 3, wherein said elastomeric coating, film or material acts as said wear layer.
 16. A sound attenuating laminated panel as claimed in claim 1, wherein an elastomeric coating is applied to a decorative paper, foils or a wood veneer used in the production of said laminated panel.
 17. A sound attenuating laminated panel as claimed in claim 16, wherein said elastomeric coating is incorporated into the adhesive used for bonding said paper, foil or wood veneer to an MDF, HDF or particleboard panel.
 18. A sound attenuating laminated panel as claimed in claim 1, wherein said elastomeric coating, film or material is applied to the edge surfaces of said laminated panel.
 19. A process for the production of a sound attenuating laminated panel, such as a laminated floor panel, having a laminate structure comprising a plurality of layers produced by lamination of said layers, wherein at least one of the layers of the laminated panel have been treated or replaced with an elastomeric coating, film or material, so as to form a treated layer, within said laminated panel, in order to reduce the noise generated by said panel.
 20. A process as claimed in claim 19 wherein said laminated panel is made by a HPL (High Pressure Laminate) or DPL (Direct Pressure Laminate) process.
 21. A process as claimed in claim 19 wherein said laminated panel comprises decorative layer, a core layer, a backing layer, and optionally, a wear layer, and wherein said elastomeric material is used to impregnate said wear layer, said backing layer and/or optionally said wear layer, when present, prior to lamination of said layers.
 22. A process as claimed in claim 19 wherein said elastomeric coating is applied as a water-based dispersion or a water-based or solvent-based solution polymer. 